ELECTRICAL CHARACTERISTICS (Continued)

APPLICATION SUGGESTION the amplifier, this to avoid "POP" and "CLICK" on

the outputs.STAND-BY AND MUTE FUNCTIONS When this voltage reaches the St-by threshold(A) Microprocessor Application level, the amplifier is switched-on and the externalIn order to avoid annoying "Pop-Noise" during capacitors in series to the input terminals (C3,Turn-On/Off transients, it is necessary to guaran- C5) start to charge.tee the right St-by and mute signals sequence. It’s necessary to mantain the mute signal low untilIt is quite simple to obtain this function using a mi- the capacitors are fully charged, this to avoid thatcroprocessor (Fig. 1 and 2). the device goes in play mode causing a loud "PopAt first St-by signal (from mP) goes high and the Noise" on the speakers.voltage across the St-by terminal (Pin 7) starts to A delay of 100-200ms between St-by and muteincrease exponentially. The external RC network signals is suitable for a proper operation.is intended to turn-on slowly the biasing circuits ofFigure 1: Microprocessor Application

Figure 2: Microprocessor Driving Signals.

+VS(V)

+18

VIN (mV)

VST-BY pin 7 1.8

1.3

0.8

VMUTE pin 6

4.1

2.9

2.3

Iq (mA)

VOUT (V)

OFF PLAY MUTE ST-BY OFF ST-BY MUTE D96AU259

(B) Low Cost Application external voltage divider.

In low cost applications where the mP is not pre- The device is switched-on/off from the supply linesent, the suggested circuit is shown in fig.3. and the external capacitor C4 is intended to delay the St-by and mute threshold exceeding, avoidingThe St-by and mute terminals are tied together "Popping" problems.and they are connected to the supply line via an